Automatic switch



Nov. 27, 1928. 1,693,027

J. ERICKSON AUTOMATIC SWITCH Filed April 29, 1921 l'm ran [Jr-- PatentedNov. 27, 1928.

UNITED STATES PATENT OFFICE.

JOHN ERIGKSON, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO

AUTOMATIG ELECTRIC INC.; OF CHICAGO, ILLINOIS, A CORPORATION OF DELA-WARE.

AUTOMATIC SWITCH.

" Application filed April 29, 1921.

The present invention relates in general to automatic switches, althoughcertain details are not confined specifically thereto; and has for itsobject the provision of certain mechanical improvements tending to makesuch switches more easily adj ustable, together with the addition ofother desirable features that will not be specifically mentioned now,but I will be explained in the detailed description which is to followand pointed out in the appended claims.

The invention is illustrated in the accompanying drawings, in which Fig.1 is a side view of the switch which is of the same general type as thatdescribed in United States patent to Clement, #1,107,153, granted August11, 1914, being, however, of the-particular type shown and described inthe book entitled Automatic Telephone Practice, by Harry E. Hershey,third edition. Fig. 2 is a detail as seen from the other side and hasparts cut away to expose more of the special indicator shown therein.Fig. 3 is an end view of the driving magnet. 25. Referring nowparticularly to Fig. 1, the bank of contacts shown therein is denotedgenerally by the reference character 2. This bank of contacts is adaptedto be wiped over by the wiper 3 and is so arranged that as soon as onewiper arm passes off the last bank contact, in rotating,-the other wiperarm comes into engagement with the first contact. In this specificswitch there is no common plate in the bank with which one of thewiperarms is in constant engagement, but the terminal 29 is oneterminal of abrush which extends to and makes continuous contact with the wiper 3,while the terminal 30, Fig. 2, is one terminal of a brush which makescontact with the wiper 4. The wiper 3, being a test wiper, has its twocontact tlps flattened out so as to be able to come into engagement witha second contact before it is out of engagement with the one from whichit is passing. Wiper 4, however, being a line wiper has its tips soshaped that it is never in engagement with more than one contact at atime. The ratchet wheel 28 and the wipers 3 and 4, together with SerialNo. 465,356.

as many other wipers as may be desired are rigidly secured to a commonspindle which is rotatably mounted in the frame 20.

The ratchet wheel 28, and likewise. the aforesaid wipers, are driven, ina forward direction only, by the driving magnet indicated by thereference character 5. Each time the said magnet is energized, itattracts the armaure 6, the top end of which is forced to the rightagainst the tension of the spring 7. The pawl 8, carried by armature 6,is caused to engage another tooth in the ratchet wheel 28 00 by thespring 9. When the said magnet deenergizes, the spring 7 forces thearmature 6, and likewise the pawl 8, to the left until the former comesinto engagement with the back stop 26.- The pawl 8 in returning to itsresting on position advances the wipers 3 and 4 into engagement with thenext set of contacts. This operation may be repeated as often asdesired.

In order to be able to adjust the normal position of the armature 6, theback stop 26 is eccentrically pivoted on the screw 25. It is obviousthen that by rotating the back stop 26 back and forth, the normalposition of armature 6 may be adjusted as desired.

In order to limit the forward stroke of armature 6, the machine screw 14is screwed into a threaded hole in the said armature.

.This screw, being made of soft iron, is really an extension of thearmature. The head of the screw is provided with a number of teeth, asshown, which engage a projection 13 on the locking spring washer 12. Inorder to keep the spring washer from turning, two ears formed thereonfit snugly in corresponding holes in the armature 6 as is seen mostclearly in Fig. 3. It is now seen that by turning the screw 14 one wayor the other, the forward stroke of armature 6 is easily adjusted, theadjustment being maintained by the locking washer l2.

Referring to the construction of the bank 2, it is seen that it isassembled entirely on the bank frame 21, which is cut from a singlepiece of heavy sheet metal. This construction has been found to be veryeconomical and satisfactory, but it sometimes happens that the frame 21becomes warped due to its being tightly screwed to an uneven shelf, orit may happen that it is not mechanically'perfect. In any event it oftenhappens that the spindle to which the wipers 3 and 4 are secured doesnot come exactly in the center of the circle of which the bank contactsform a part, when the switch is finally assembled and mounted in theplace in which it is to remain permanently. In that event it isdesirable to be able to adjust the relative positions of the bank frame21 and the switch frame 20 so that the center of the spindle to whichthe wipers are secured coincides with the center of the circle of whichthe bank contacts form a part. It will be noticed that the beforementioned frames are fastened together by the two screws 22 and 24. Inaddition there is provided a hollow set screw 23 which is screwed into athreaded hole in the frame 20. By loosening the screw 22 and turning theset screw 23 backward and forward and again tightening the screw 22, theframes 20 and 21 are brought closer together or pushed farther apart,thereby adjusting the before mentioned centers in one direction. Inorder to provide for a slidin adjustment between the frames 20 and 21, te hole in the set screw 28 is purposely made larger than the screw 22,and the hole in the frame 20, through which the screw 24 passes, isslotted lengthwise the frame so as to allow the latter to slide backwardand forward.

Another feature of the present invention relates to the pawl spring 9,which is peculiarly constructed so as to facilitate its easy removal.The spring normally fits into a groove, cut in the extended pivot 10.Now, when it is desired to remove the said spring it is necessary onlyto unclip the same from the armature 6 and remove it from the pivot 10,as the coil in the said spring is made sufficiently large to allow it tocome off easily.

Referring now particularly to Fig. 3, the rod 35 on which the armature 6is pivoted is recessed at both'endsand the slotted spring 36 engages therod at the recesses in the manner shown, so as to retain the rod inposition.

As has been mentioned before, Fig. 2 is a detailed showing of'anindicator, denoted by the reference character 27. Little need be said inthis connection except that the pointer 31 points to the number on therotatable indicator 27 that corresponds with the set of contacts uponwhich the wipers are standing.

.Having described my invention, what I consider to be new and desire tohave protected by Letters Patent will be pointed out in the appendedclaims.

What I claim as my invention is:

1. In a step by step switch, a driving magnet, an armature for saidmagnet, and a pole piece inserted in said armature adjacent to the coreof said magnet adapted to engage the core when said armature isattracted, said pole piece being adjustable relative to the armature tolimit the stroke thereof.

2. In a step by step switch, a driving magnet, an armature for saidmagnet, a threaded hole in said armature opposite the pole of saidmagnet, an adjustable pole piece screwed in said, hole and adapted toregister with the core of said magnet when the same is ener gized, andmeans for preventing said pole piece from turning in said hole. I

3. In a step by step switch, a driving magnet, an armature for saidmagnet, a threaded hole in said armature opposite the pole of saidmagnet, an adjustable pole piece screwed in said hole and adapted toregister with the core of said magnet when the same is energized, a headfor said pole piece on the opposite side of the armature from themagnet, and a spring washer between the head and the armature to keepthe pole piece from turning.

4:. In a step by step switch, a switch frame, rotatable wipers anddriving mechanism therefor mounted on said frame, a series of bankcont-acts mounted in the arc of a circle on another frame separate fromsaid switch frame, means for securing the two frames together with theaxis of the wipers approximately in the center of the banks, and meansfor adjusting one frame relative to the other to exactly position saidwipers.

5. In a driving mechanism for an automatic switch, a ratchet wheel, anarmature, a pawl pivoted on said armature and adapted to engage theteeth of said ratchet, a projection on the pivot and an enlarged headforming a recess between the head and pawl, and a coil spring mounted onthe pivot in said recess, one end of said spring engaging the pawl andthe other the armature, and the diameter of the coils being large enoughto permit the spring to he slipped over the said head.

6. In a step by step switch, a switch frame, movable Wipers and drivingmechanism therefor mounted on said frame, a series of sets of bankcontacts mounted on another frame,

means for securing said frames together to enable said wipers to engagesaid contact sets successively, and means for adjusting one framerelative to the other in order to exactly position the wipers on anycontact set which they engage.

7 In a step by step rotary switch, a series of bank contact setsarranged in a semi-circle, two sets of wipers 180 apart adapted toengage said contact sets successively, and means for indicating thenumber of the bank contact set with which the wipers are engaged, saidmeans comprising a pointer and a dial bearing duplicate series ofnumerals, one series for each wiper set, arranged in a complete circle.

8. In a switching device, bank contacts, a wiper adapted to successivelyengage said contacts, a dnving magnet, an armature for said magnet, apawl pivoted to said armature, a crum, the coil being large enough topass over serrated driving wheel for moving said wiper, said head wheneither end of said spring is 10 a removable coil spring formaintainingsaid not in position, and being reduced in size pawl in operativerelation with said wheel, and held in position by said head when bothand a fulcrum for said coil spring having a ends are in position.

flattened head, the ends of said spring engag- In Witness whereof, Ihereunto subscribe ing the armature and pawl, respectively, and my namethis 22d day of April, A. D. 1921.

the coil of said spring encircling said ful- JOHN ERIGKSON,

